This is a good question. This means that something is not configured correctly with the component selected when these errors print. It's the framework telling you something isn't right. Architect 2.1 didn't relay this information. 99.9% of the time this same error will show up in the browser as well.

This error does not show up any more in Log popup. And my browser console is clean.
It seems that error only came up during/after project ugrade.
SA 2.1 did not relay this error
SA 2.2 do not relay this error any more.

framework error: Cannot read property 'buffered' or undefined

After upgrading my rather large project from v 2.1.0 to 2.2.0, immediately after the upgrade the project looks okay but after going through several screens the Architect UI freezes. Upon consequent loading of the project i get Error: Level , Category: Project, Message: "framework error: Cannot read property 'buffered' or undefined" messages every time i attempt to access several sections of the project. The design does not render anything when that happens. I have spent 5 hours to narrow the issue down. All i can see is if i change a store of a grid , access another component that doesn't experience the issue and go back the problem is gone until i reload the architect on the project.
I have several of those grids and there is the same problem on all. I have no problem running the app using EXT JS 4.1.1 and EXT JS 4.2, nor did i have any problems with v 2.1.0.
It is great to have a LOG in Architect, but the message is not helpful in any way to understand where the issue may be.

It sounds like the grid is unable to find the store you've bound to it. What happens when the app runs in the browser? You should be able to get a similar error with full stack trace capabilities in the debugger.

yoann and alphimax - we'd be happy to take a look at your project and upgrading it. If you send an archive of your project pre-2.2 upgrade. We'll see if we can do an investigation on our side.

Way to many bugs, moved back to 2.1.0 for now
I narrowed this further and it has something to do with the naming of userClassName and the Store being the same value.
In my case i have a Store and Model with the same "id" and "userClassName".

Another issue I also see is that upon upgrade i have several models with "defaultValue" set as some string, and upon upgrade those are converted to integers and the single quotes are removed.
Changing it back to string still causes warnings (with red exclamation mark) - Invalid value,config value converted to string.

There are several window pop-ups that once you get to them it is not possible to click on any of the buttons. Seems that they get out of focus.